(19)
(11) EP 0 385 666 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
10.04.1991 Bulletin 1991/15

(43) Date of publication A2:
05.09.1990 Bulletin 1990/36

(21) Application number: 90301943.8

(22) Date of filing: 23.02.1990
(51) International Patent Classification (IPC)5: B60C 9/00, B60C 9/20
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 27.02.1989 JP 43205/89

(71) Applicant: THE YOKOHAMA RUBBER CO., LTD.
Tokyo, 105 (JP)

(72) Inventors:
  • Susumu, Imamiya
    Hiratsuka-shi, Kanagawa-ken (JP)
  • Hisao, Katoh
    Hiratsuka-shi, Kanagawa-ken (JP)
  • Yukio, Tozawa
    Hiratsuka-shi, Kanagawa-ken (JP)

(74) Representative: Bridge-Butler, Alan James et al
G.F. Redfern & Co. Redfern House 149/151 Tarring Road
Worthing, West Sussex BN11 4HE
Worthing, West Sussex BN11 4HE (GB)


(56) References cited: : 
   
       


    (54) Pneumatic radial tire


    (57) A pneumatic radial tire for passenger cars and heavy duty use is disclosed, which tire has a rubber coated steel cord layer applied inter alia to its belt portion. The cord (10) consists of a pair of steel filaments (11a, 11b) whose preform ratio "K" is set in the range of -K₁ + 2.05 ≦ K₂ ≦ -K₁ + 2.50. Conformance to this preform ratio "K" provides filaments (11a, 11b) with periodically alternate contact and non-contact regions (A, B) longitudinally of the cord (10).







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